Refactor shared layouts and remove unused CSS

app/static/style.css

@@ -1,9 +1,93 @@
-.link-button {
-  border: 1px solid black;
-  padding: 10px;
-  text-decoration: none;
-  border-radius: 5px;
-  background-color: lightgray;
-  color: black;
-  margin: 5px;
+:root {
+  --bg: #f4f6f8;
+  --surface: #ffffff;
+  --border: #dde2e8;
+  --text: #111827;
+  --muted: #5f6b7a;
+}
+
+* {
+  box-sizing: border-box;
+}
+
+body {
+  margin: 0;
+  font-family: "Segoe UI", sans-serif;
+  color: var(--text);
+  background: var(--bg);
+}
+
+.public-wrap {
+  max-width: 1000px;
+  margin: 0 auto;
+  padding: 24px 20px;
+}
+
+.public-card {
+  border: 1px solid var(--border);
+  background: var(--surface);
+  border-radius: 8px;
+  padding: 18px;
+}
+
+h1 {
+  margin: 0 0 10px;
+}
+
+.muted {
+  color: var(--muted);
+}
+
+.public-actions {
+  display: flex;
+  gap: 8px;
+  flex-wrap: wrap;
+}
+
+.auth-form {
+  display: grid;
+  gap: 8px;
+  margin-bottom: 10px;
+}
+
+.auth-form input {
+  border: 1px solid var(--border);
+  border-radius: 4px;
+  padding: 9px 10px;
+  font: inherit;
+}
+
+.link-button {
+  display: inline-block;
+  border: 1px solid #111827;
+  padding: 8px 12px;
+  text-decoration: none;
+  border-radius: 4px;
+  color: #111827;
+  background: #f3f4f6;
+  cursor: pointer;
+  font: inherit;
+}
+
+.flash-stack {
+  margin-bottom: 10px;
+  display: grid;
+  gap: 8px;
+}
+
+.flash {
+  border: 1px solid var(--border);
+  background: var(--surface);
+  border-radius: 6px;
+  padding: 10px 12px;
+}
+
+.flash.error {
+  border-color: #f0c2c2;
+  background: #fef2f2;
+}
+
+.flash.success {
+  border-color: #b7dfc3;
+  background: #ecfdf3;
 }